2006 Prius clock spring (spiral cable) repair

So both defrost buttons, the recirculate, and the info button on the right hand side of the steering wheel have never worked since I bought the car used a few years ago. After taking the steering wheel apart, I see that buttons are just providing different resistance values back to the car. After searching this awesome site (I do know how to search!), I found I wasn't alone:
Suddenly, some buttons on steering wheel mounted controls aren't working! Any ideas? | PriusChat
Exact same buttons. Hmmm. I decided to try and fix it myself. Unfortunately, I didn't take any pictures of removing the clock spring, but you can see some here:
Can I avoid replacing my failing clockspring (spiral cable)? | PriusChat
Yes, you must remove the airbag and the steering wheel to get to it. No, I did not disconnect any batteries, and I might have waited about 30 seconds before I had the airbag off. I do use a wrist strap to ground to the car though, but all the airbag connectors are self shorting anyway.
Sorry that some of the pictures are horrible.

To get the clock spring apart, you first have to release 4 plastic tabs in the center of it.

Then the center part comes out.

After removing the outer ring (held with more plastic clips), the cables are free.


Here is a close up of the plastic tabs that need to be released to get it apart:
And here is the bad spot in the cable:

As you can see (above), the 4th and 5th wires from the bottom do not have continuity. This is only 1 of the 2 ribbon cables in the clock spring. I think the 2 larger traces at the top of the cable are for one of the squib circuits for the airbag. The second ribbon cable (with no damage, thankfully) looks identical, so I assume the larger traces on it are for the secondary squib circuit on the airbag as well.

To repair, I had to scrape off the insulation until I found good copper to solder to (I've already done the lower one in the shot above) and carefully solder new wire to bridge the gap in the original traces.

I took some wire I had (I'm guessing about 22 gauge?) and peeled off 3 of the strands. I twisted them together, tinned it, and used it to bridge both gaps in the ribbon cable.

Now, you can't see in the picture, but I burned a hole right through the ribbon cable trying to tin the copper so I could attach the wires. This stuff is paper thin! I was a production solderer for 8 years soldering SMT components on a daily basis, but this was one of the most challenging jobs I've ever done. I used a Weller WTCPT production station with a PTS8 tip. If you don't know what any of that is, please do not attempt this repair!

Finally got them both connected. Continuity was checked with my Fluke. Good to go.

Now to reassemble: Be sure to run the ribbon cable back through the slot in the plastic ring, then snap it back on.
I slowly wound the cable back into the housing. See that spike of plastic sticking up? That indexes to the inner hub here:

Ensure that the inner hub is going to line up correctly:
Snap it back together. Slowly spin it and see that nothing is binding, and check continuity again.
Slowly turn the inner hub until you can see the orange disc in the window, and the arrows below line up:

Now it is centered and ready to install on the car, assuming you pulled the steering wheel with the tires pointed directly ahead.
No orange disc means it is not centered. Carefully spin the inner hub ring until it appears.

So for about an hours worth of time, I saved $213.68 plus shipping (cheapest dealership I could find was Olathe Toyota in Kansas City). I'm just happy I can use the defrost without having to push buttons on the MFD when it is cold outside.
If my repair eventually fails, I'll post back.

 

Thanks for the info, I didn't realize they were that cheap.
I have no clue how the wires in the MIDDLE of the cable broke, but it looks like they either rubbed as the cables slid past each other, or that they got hot. Seeing as how the circuit is probably low current, I doubt it was the latter. There was some kind of grease inside the clock spring, I wonder if it slowly ate through the plastic somehow? Any recalls from Toyota on clock spring grease?
I also hunted all over looking for a schematic, but the best I could find is only of the radio buttons on the left side of the steering wheel:

 

Well, it lasted for a while, but now my defrost and info buttons don't work again. Ebay here I come.

 

Well, the $25 ebay clock spring that I bought last year lasted a little over 1 year before it failed. No lights in the steering wheel, and defrost and info buttons were the first to go. Now almost no button on the wheel works, and there is an "open in airbag squib circuit B" airbag light on. I'm starting to see a trend here....
I also see there is now a 1 year warranty on the ebay clock spring! Oh yipee.
My dad's voice and "you get what you pay for" are echoing through my head....

 

People, don't cheap out on the clockspring/airbag connector. I'm sure you life is woth the extra $175?[/QUOTE]
The way Takata airbags are going now, it might save your life if it doesn't go off! Besides, I'm well insured and my wife could have a heck of a shopping spree...
I just ordered another $25 from the A-store